Hassasin
Member
Looking at how Leitz went about front ring design on this Summitar 50 2.0 lens, dedicated filters were made to match. Filter thread is in deep recess and filters are built to match. One thing to get the original filters, but there is also an adapter made in China (not sure if Leica ever made one) that will allow 39mm filters to mount. Problem I see is vignetting issue. Looks like a rue thing if any number of filters are stacked, but even with just one optical path becomes even more restricted.
Has anyone used this kind of adapter? LINK
Has anyone used this kind of adapter? LINK